Ureteral stents, which function to provide drainage from the kidneys to the bladder, are placed in position in the ureter through an appropriate scope system, typically in retrograde fashion through a cystoscope having a working channel large enough to put the required instruments through, such as stents, guide wires, forceps and the like. Placement of such a large scope into a patient's urethra requires anesthesia and a "cysto-room" environment.
After the scope is placed through the urethra and the tip is within the bladder, the stent is then advanced through the scope, through the bladder and into the ureter. At the point where the stent or part of the stent is in the ureter, the tip of the stent and its full location is no longer visible directly by means of the scope, the scope being too large to itself also be advanced into the ureter. Thus the stent and guide wire must be positioned and progress must be viewed by means of fluoroscopy or ultrasound from outside the patient. Manipulation of the stent and cystoscope while trying to interpret the image given by either fluoroscopy or ultrasound can become quite difficult. In any event, after the stent is in the desired location as detected by a combination of direct vision and fluoroscopy or ultrasound, the stent is left in place by some means of pushing the stent off of its working guide wire or stylet, after which the guide wire or stylet is removed, followed by the removal of the scope from the urethra.
This procedure, though quite routine, is quite cumbersome, as the doctor operating the cystoscope must be sitting low between the patient's legs, and must bend over to view through the cystoscope. Since direct vision is lost anywhere past the bladder, it is not possible for the doctor to actually see where the stent is going, what the condition of the ureter is, what potential obstructions look like, or if a kidney stone is embedded within the walls of the ureter. Thus upon encountering an obstruction, the doctor's options are highly limited, the most obvious option merely being to try to negotiate past the obstruction and proceed with the placement of the stent irrespective of the nature of the obstruction, presence of a kidney stone, etc. For this purpose various forms of stents and guide wires are known.
One form of stent and guide wire system is shown in U.S. Pat. No. 4,307,723. As shown therein, the stent is an elongated, flexible, generally cylindrical member having the proximal end of the stent closed and set in the form of a hook, with the other end also set in the form of a hook with a longitudinal intermediate portion connecting the hooked ends. A stylet is inserted through the open end of the stent and passed through substantially the full length of the stent to straighten both hooks. Also, a stent pusher is threaded over the wire stylet and inserted into the open end of the stent a certain amount to allow the partial withdrawal and redirection of the stent if necessary during the retrograde cystoscope insertion process hereinbefore described. Once the stent is properly positioned, the stylet and stent pusher are removed by withdrawing the stent pusher while holding the wire stylet, causing the stent and stent pusher to disengage, after which the wire stylet and then the stent pusher are withdrawn.
Other stents are of somewhat similar construction to the foregoing though open at the proximal end, with a stent pusher being used to push against the distal end of the stent to encourage the same to move together with (or after) the guide wire into position, after which the stent pusher is used to retain the stent in position as the guide wire is withdrawn, with the stent pusher itself then being withdrawn.
In U.S. Pat. No. 4,610,657, a ureteral stent is disclosed having both ends thereof open, but with the opening at the proximal end being smaller than the opening of the lumen and distal end. In this way, a small guide wire may be inserted through the lumen and through the proximal end to negotiate past obstructions, etc., or alternatively a larger guide wire could be inserted to pass through the lumen, but not through the smaller opening in the proximal end, to act as a stent pusher for stent insertion purposes.
In addition to the foregoing, two-piece guide wires are also known. Such guide wires generally comprise a helically wound flexible outer guide wire portion typically closed at the proximal end, and a solid, more rigid inner guide wire removably positioned within the flexible outer guide wire portion. In this manner, the two guide wire members together may be used as a single guide wire and if necessary, the more rigid central guide wire may be partially withdrawn, making the proximal end of the outer guide wire member more flexible to better manipulate the same past obstructions (See, for instance, U.S. Pat. No. 4,713,049 for a dual guide wire system of this general type).
Obviously, from the foregoing description, cystoscopes for passing through the urethra and into the bladder and having an auxiliary port for insertion of the stent, guide wire, pusher, etc. are well known. In general the auxiliary port of such devices is located to the side of the fiber optic scope, which scope is normally as large as or larger than the stent itself. Thus the overall combination of the fiber optic bundle, cystoscope body, stent, stent pusher, guide wire, etc. is relatively large, requiring that the patient be anesthetized as mentioned before, and being much too large for passage beyond the bladder into the ureter. See for instance, U.S. Pat. No. 4,738,659 disclosing a catheter for use with a cystoscopic lens. Also, of course, such fiber optic scopes are themselves well known in the prior art, such as by way of example as disclosed in U.S. Pat. No. 3,417,745.
In U.S. Pat. No. 5,159,920, a scope and stent system is described, the scope providing visibility not only through the urethra but also through the ureter during the insertion and placement of a ureteral stent. The scope is in the form of a fiber optic bundle having an appropriate provision for lighting and lensing thereof, and preferably having a video camera and monitor responsive to the image formed at the opposite end of the scope for viewing during the scope insertion process. The fiber optic bundle itself is made sufficiently small so that the entire scope may be fabricated with the appropriate dimensions of a typical stent guide wire and made sufficiently flexible for negotiating a tortuous path as required. The scope may be first inserted through an open-ended stent and through the urethra, the bladder and the ureter, and then the stent inserted thereover through the use of an appropriate stent pusher, or alternatively the scope, stent and stent pusher may be advanced together, the scope allowing observation of the procedure and the nature and extent of any obstructions encountered in the insertion process. Alternate embodiments include the provision of an additional working channel within the stent to allow an additional instrument such as a laser lithotriptor to be utilized in conjunction with the placement of the stent, as well as alternate forms of scope systems.
However, in spite of all of the advances made and described above, the ureter remains one of the most frequently damaged structures in intra-abdominal and/or retroperitoneal surgery. It is estimated that in 0.5% to 1-3% of pelvic operations, some type of ureteral injury will occur and this percentage is estimated to increase to 30% for radical procedures for malignant conditions. Operations of this nature may entail dissection, clamping and ligation close to the ureter that is displaced from its normal course, and prone to injury. With the increasing frequency with which more complex gynecological procedures are being performed laparoscopically, this rate is bound to rise. The reasons for this are several fold, but include the variable course of the pathway of the ureter, the fact that each individual is basically "unique" insofar as the precise location of the ureter, and the proximity to vascular structures to be ligated. In females, the proximity of the ureter to the uterosacral ligaments, makes it difficult to delineate these two structures from each other. Additionally, bleeding in the pelvis makes it very difficult to appreciate the fine structures and their anatomic course. In the male pelvis, ureteral injury is usually secondary to either cautery or direct instrument trauma when completing the cephalad extent of a pelvic lymph node dissection. It is at this end-point in the dissection that accumulated blood in the region of the iliac artery and its branches, can easily obscure vision and promote inadvertent ureteral or vessel injury.
Ligation or damage to one or both of the ureters significantly raises morbidity (and even mortality in extreme cases) post-operatively. The problem that exists is that the intraoperative "real-time" techniques that give the surgeon information as to the ureters' course during the procedure or operation are not helpful in the minimally invasive surgery of today.
The problem remains however, that most ureteral injury is not recognized during the surgical intervention. It is reported that less than one-third of the injuries are recognized intraoperatively. The diagnosis is typically made at a later date when the patient presents signs and symptoms suggestive of ureteral injury, e.g., persistent abdominal and/or flank pain, abdominal distention, and fever.
Traditional methods which help delineate the structure are imaging (using material seen on a screen) pre-operatively, intraoperative fluids or dyes concentrated in the urine (to check for leakage if the structure is transected during the procedure), or ureteral stents or intralumen tubes, which are placed preoperatively or intraoperatively to delineate the course of the structure.
Retrograde imaging (cystoscopy involving insertion of an imaging scope via the bladder) requires a skilled operator and is also limited in degree of visualization. Fluids or dyes (such as indigo carmine, sterile milk, methylene blue, etc.) only will show up or "spill" once transection has taken place. If the ureter is kinked or tied off by suture, no dye will spill, but the ureter may be compromised to the same degree. Ureteral stents are placed pre-operatively and can be detected by manual sensation. They are good for "open abdomen" laparotomy procedures where the surgeon can feel the tube. In minimally invasive surgery, the surgeon cannot place his or her hand into the abdomen to feel the stent. Additionally, depending on the overlying pathology (e.g., dense adhesions and thickened scarring, tumor or other pathology), even the sensation of touch does not always clearly allow the surgeon to know the ureter's course with accuracy or surety.
There still exists the need for an illuminated stent that could be used to enhance visualization of this easily damaged structure. By using sight rather than touch sensory feedback, lighted stents could be placed pre-operatively or intraoperatively to aid the surgeon in both open laparotomy and closed abdomen minimally invasive surgical procedures. This would give "real-time" and continuous information to the surgeon as clamps and/or sutures were being placed during the procedure to lessen the likelihood of damage.